Screening device



April 17, 1962 A. J. ROUBAL SCREENING DEVICE 2 Sheets-Sheet 1 Filed June8, 1959 April 17, 1962 A. J. ROUBAL SCREENING DEVICE 2 Sheets-Sheet 2Filed June 8, 1959 Aqkkome/y,

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This invention relates generally to screening machines or apparatus foruse in connection with screening ofmaterials and like operations. Moreparticularly, this invention relates to a gyratory screen machine of thefour bearing type wherein the gyrating screen body is both supported andstabilized by resilient mounts strategically interposed between outerbearing housing extensions and other parts of the structure to provide adevice in which the vibrations resulting from the operation thereof aresubstantially completely isolated from the building in which the screenis mounted.

For purposes of this description, a four bearing screen may beconsidered as being in part a conventional two bearing screen having tworunning shaft projections extending outside of its balance wheels. Sucha two bearing screen, however, becomes a four bearing unit because theseshaft projections are journaled into outer bearings which thus carry theentire weight of the screen. In prior art machines, as exemplified byParks, US. 2,212,550, these outer bearings in turn are carried on astationary frame which rests on or is suspended from the buildingfloors.

In order to keep the screen on its proper angle, it is necessary tostabilize the body. Screens have heretofore been stabilized by means ofsprings placed near each corner of the screen body. Such a screen bodycan be perfectly balanced under no load conditions so that the axis ofgyration exactly coincides with the center of the outer bearings and novibrations will go into the building.

When, however, the screen weight changes due to the nonuniformity ofloading during operation, or when materials stick to the deck, or whenchanges occur in the weight of the screen cloth, the screen becomesunbalanced. Since, in the screens of the prior art, the outer bearingsof the screen are mounted rigidly to the supporting frame which is, inturn, rigidly secured to the building, the amount of out of balance willbe transmitted directly to the building. When this occurs in a buildingwhich has an extra amount of steel, the screen will lose only a smallamount of throw. However, when the building steel is no heavier thanthat required to carry the dead-weight load, as might be normallyexpected, the screen will lose a considerable amount of throw and thebuilding will vibrate an amount almost equal to the loss of throw of thescreen.

The present invention is predicated upon my discovery that, byresiliently mounting the screen body directly to the outer bearinghousing and then resiliently mounting the outer bearing housing directlyto a supporting structure, substantially all of the vibrations resultingfrom an out-of-balance condition in the screen body will never reach thesupporting structure but instead will be ab-I sorbed directly in theamounts which, when made according to my later description, possess aunique propensity and efiiciency to absorb vibrations. Thus, in thescreen of the present invention, as will be more fully de-- scribed,each outer bearing is carried in a housing having a pair of armsextending oppositely therefrom and each arm is supported by two sets ofresilient mounts, one set of mounts being carried by the bearing housingarm near each corner of the screen body and resiliently connecting thebody to the arm, and the other set of mounts resiliently connecting thearm to a stationary.

supporting structure. With this arrangement, only four Patent mounts arerequired to support the entire live weight of the screen relative to thebuilding and only four more mounts are required to stabilize the screenbody.

When the amount of eccentricity machined in the shaft is equal toone-half of the screen throw and the screen is then properly balanced,the outer hearings will have no motion while the screen body has itsfull circular motion. Consequently, during operation of the screen, thefour mounts which are placed between the outer bearing housing arms orextensions and the stationary supporting structure (which may beconsidered as part of the building) do not vibrate while the four setsof mounts which resiliently connect the screen body to the outer bearingarms do vibrate but are isolated from the building. And this is trueeven when the screen has a fairly large load of material.

If the screen is excessively overloaded, the throw of the screen will bereduced and the outer bearing arms will take on a slight circularmotion. Under this condition, the screen is out of balance and somevibrations will be transmitted to the building. However, even underthese extreme conditions, the shock load transmitted to the building issubstantially minimal as a result of the requirement of my design thatsuch load pass through the stabilizing mounts, the arms and thesupporting mounts before it ever reaches the structure. Because of thelarge deflections initially placed in the mounts by the screen deadweight in accordance with this invention, substantially all of the shockis absorbed in the mounts with the result that little, if any, everreaches the supporting structure. In my arrangement, it thus becomesapparent that the deflections of the carrying mounts and the bodystabilizing mounts become additive.

The carrying or supporting mounts of the screen of the presentinvention, unlike those of the prior art, are not affected by the screenthrow and therefore will give long life. Further, when the uniquecompression mounts described in my copending United States application,Serial No. 835,744,'filed August 24, 1959, are used with the screen,replacement of the mounts takes considerably less time than has beenheretofore possible.

Accordingly, one of the prime objects of this invention is to provide animproved four bearing screen which is completely balanced relative to,and therefore will not cause vibrations in, its stationary supportingstructure during normal operation.

Another object of the present invention is to provide a new four bearingscreen design in which vibrations of operation are isolated from thestationary supporting structure to which it is mounted by thepreoperative static deflection and strategic placement of resilientsupporting mounts therein.

Another object of the present invention is to provide a new four bearingscreen design in which balance between the screen body and specialextensions outreaching from outer bearing housings is obtained by thereaction to the action placed upon a series of novel resilient mountsstrategically disposed relative thereto.

, Still another object of the present invention is to provide a new fourbearing screen design which, even under severe shock, permits onlyminimal transmission of such shock to the building in which it ismounted.

A still further object of the present invention is to provide animproved balanced four bearing screenin which the outer bearings remainstationary throughout normal' In the drawing in which like parts bearlike numerals throughout the several views:

FIG. 1 is a plan view of a vibrating device embodying the presentinvention;

FIG. 2 is a side elevation of the device in FIG. 1;

FIG. 3 is a cross section taken along line IlIIII of FIG. 2 showing astabilizing mount of the type herein contemplated;

FIG. 4 is a cross section taken along line IV-IV of FIG. 2 showing asupporting mount of the type herein contemplated;

FIG. 5 is a side elevation of another vibrating device embodying avariant of the present invention; and

FIG. 6 is a cross section taken along line VI--VI of FIG. 5.

By way of example, one embodiment of my invention is shown in connectionwith an apparatus for screening materials in which the numeral 11indicates the stationary base or supporting structure which may consistof a plurality of channel rails 12 or like member carried by appropriatecompanion resilient gyratory supporting bodies or bearings 31, 32,herein called inner bearings. The drive shaft 30 is continuous anduninterrupted and is provided adjacent its opposite ends with aplurality of journal portions which are mounted within the bearings 31,32 fitted respectively in the adjoining side walls 19, 20 of the screenbody 13 and extend therefrom through suitable inertia controlling meanssuch as flywheels 33, 34 into second bearings 35, 36 respectively fittedin the adjoining gyratory supporting body. Bearings 35, 36 are outboardof bearings 31, 32 and the therefore herein called outer bearings. Theaxis of the outer bearings is offset from the axis of the inner bearingsby the amount of eccentricity in the shaft, for example, one-half of thetotal throw desired in the screen body.

Each of the outer bearings 35, 36 is enclosed by a suitable outerbearing housing 37, 38 respectively. Each outer bearing housing, forexample, housing 37, is provided with a pair of outwardly extending armportions or extensions 39, 40, the full significance of which will bemore fully explained.

One end of shaft 30, for example, the end passing through inner bearing32, flywheel 34 and outer bearing 36, is provided with a furtherextension 41 to which is secured a pulley 42 for a driving connection toa source of power. A suitable linkage such, for example, as V- belts 43,connects pulley 42 with driving sheave 44 secured to the drive shaft 45of a suitable motor 46 mounted adjacent screen frame 13 as on a pedestal47. As shown, shaft extension 41, that is, the pulley receiving portionof the shaft 30, is concentric with the actual center thereof. Motor 46may comprise any supports (not shown).

Numeral 13 indicates the screen body or frame which is freely orresiliently suspended from the base 11 and into which a gyratory motionis imparted for effectually screening materials delivered thereto. Asshown, the screen body or frame 13 is inclined in the conventionalmanner to permit the flow of material therethrough and is provided withtwo screen decks 14, 15 disposed in the usual vertically spacedrelationship to each other and comprising a screen cloth 17 and clampingmeans 18 for securing the cloth 17 to the screen body 13. It is, ofcourse, understood that any desired number of screen decks may beemployed according to the exigencies of the operations.

The screen body 13 as shown further includes upwardly extending sideplates 19, 20 which reach above the upper screen deck 14 to prevent thelateral loss of material and backing plates 21, 22 which preventspillage of material at the feed end of the screen. Clamping means 18are normally attached to the side plates 19, 20. Adjacent the dischargeend of the screen, suitable chutes 23, 24 are provided for each deck fordirecting the flow of the material from the screen deck into a desiredcontinuation 4 of the unit process involved such, for example, as aconveyer, a scrubber and the like.

The means for gyrating the screen body is preferably constructed asfollows: the screen body 13 is balanced or supported for gyratorymovement midway of its ends on a transverse driving shaft 30 whichpasses through the side walls 19, 20 of the body 13 and which issupported at its opposite ends in a free floating fashion in and by suitable source of motive power although electrical motors are generallypreferred.

Gyration of the screen body 13 is thus readily achieved by the actuationof the motor 46 which, in turn, drives sheave 42 through sheave 44 andlinkage 43 whereby gyrating shaft 30 is rotated in bearings 31, 32, 35,36 and with flywheels 33, 34 to impart gyratory movement to decks 14,15.

Referring now to the outer bearing housing previously described(considering housing 37 in FIG. 2 as exemplary), each housing isprovided with outwardly reaching arms or extensions 39, 40 which, aspreviously described, extend from opposed peripheral portions of theouter bearing housing 37. Each of the arms 39, 40 extends generallylongitudinally of the screen body 13 and terminates adjacent the endsthereof such as is shown in FIGS. 1 and 2. Of course, a likeconstruction is provided on the opposite side of the screen body 13where arms 39a and 40a extend outwardly from hearing housing 38.

Adjacent the ends of each arm, for example, arm 39, and intermediate thearm and the screen frame 13 is interposed a shear mount 51 whichresiliently connects the arm end to the screen frame 13. A like mount 52is provided intermediate arm 40 and frame 13 adjacent the end of arm 40.

Another pair of resilient mounts 53, 54 are deployed adjacent mounts 51,52 and outer bearing housing 37 on arm portions 39, 40 respectively insuch a manner that one mount is connected between each of the arms andthe portion of supporting structure 11 adjacent thereto. Thus, mount 53resiliently connects arm 39 and supporting structure 11 and mount 54resiliently connects arm 40 and supporting structure 11. While mounts53, 54 are shown within the span of mounts 51, 52, satisfactory resultsare also obtained when one or both of the sets are interchanged. As amatter of preferred design, however, the

mounts will connect to the arms nearer to the ends of the arms than tothe outer bearing housing.

Suitable mounts for use in this structure include those especiallydesigned by me and described in my aforementioned U.S. application. Anyother of the conventional' resilient mounts, such as those described inParks U.S. 2,066,362 and the like, may be likewise employed with equalfacility in connection with this invention provided the spring assembly,as the mounts are herein called, possesses the facility to be mounted sothat mounts 51 and 52 and 51a and 52a, those corresponding thereto onthe other side of the device, function to stabilize the screen andmounts 53 and 54 and 53a and 54a, those corresponding thereto on theother side of the device, function to absorb the shock emanatingtherefrom.

Referring now to FIGS. 3 and 4, representative stabilizing andsupporting mounts are shown. The stabilizing mount 52, shown enlarged inFIG. 3, is mounted intermediate screen body 13 and outer bearing housingextension 40 and comprises a mount housing 55 having detachable endplates 56, 57 secured thereto defining a substantially rectangularopening 58 therewith. The outer bearing housing arm 40 is slotted at 59to provide communication between opposed sections 60, 61 of the mount52. Each section comprises first and second complementary wedge portions62, 63 respectively, having a cylindrical wedge portion 64 interposedtherebetween to provide a shear mount having opposed surfaces generallyparallel to each other. When the sections are engaged as shown so thatone (for example 60) is the mirror image of the other (for example 61),a mount 52 is provided which may be readily mounted within therectangular opening 58 defined by housing 55 and end plates 56, 57 inthe manner shown. It has been found, however, that in the purview of thepresent invention any of the well known conventional resilient mountsmay be utilized, adapting the mount housing to conform thereto, providedthey still resiliently connect the specified members of my device.Similarly, the slotted opening 59 defined in arm 40 is described merelyto exemplify one method of installing the representative modular unitsand it is not intended to provide a limitation to the present invention.

In FIG. 4, a representative supporting mount 54 is shown comprisingarrangement of modular mount sections 71, 72 generally similar to thestabilizing mount except that they have been reversed to provide anangle of incidence between the modular units which is divergent up-Wardly instead of downwardly as in the case of the stabilizing mounts toillustrate another mounting arrangement which may be employed with mydevice.

In illustrating the supporting mount, I have chosen a variant seatingstructure for the modular sections. Thus, the bearing arm 46 is providedwith first and second oppositely disposed mount seats 73, 74 having athin (relative to the full thickness of the arm) central wall portion 75interposed therebetween. Surrounding this portion of arm 40 is asupporting mount housing 76 having a body portion enclosed by detachableend plates 77, 78 and attached to supporting structure 11 in a suitablefashion.

In the embodiment described, the screen body has a circular motion andthe outer bearing arms have no motion when the screen is properlybalanced. Thus, before connecting the stabilizing mounts 51, 52, 51a,52a between the arms 39, 40, 39a, 40a and the body 13, the inch-poundsof the complete screen body 13 must be equal to the sum of theinch-pounds of the shaft 30 and the counterbalancing wheels 33, 34, atwhich time the center of gyration is coincident with the center of theouter bearings. The action which results when the body stabilizingmounts are connected is met with an equal and opposite reaction at theouter bearings. Thus, no movement of the arms takes place.

An important aspect of the present invention thus presents itself inthat each outer bearing housing is, as previously described, providedwith outwardly extending arms which are, adjacent their respective ends,resiliently connected to the screen body and to the supporting frame byindependent resilient shear mounts which are prebiased to provideopposing force moments relative to the locus of the outer hearing. Thehigh static deflection imparted to the several mounts, and the novelcoaction of the mounts with the bearing housing arms and their novelarrangement relative thereto, is believed to be an important reasonattributing the vastly improved operating characteristics to my screen.

An alternate embodiment of the present invention which is especiallysuitable for installation where space requires that the screen besuspended from an overhead structure is illustrated in FIGS. and 6. Theprimary advantage of my construction, namely, that better vibrationcontrol can be achieved when the screen is out of balance due tooverload or material adhering to the deck, is substantially obtainedwith this low space variant. In both structures, however, considerablyless shock intensity is transmitted to the mechanism bearings, and henceto the buildings when large feed is dropped onto the screen, thanheretofore obtained by the structures of the prior art.

Specifically, the embodiment of FIGS. 5 and 6, which as previouslystated is especially adaptable for installations where spacerequirements preclude on-the-floor mounting, comprises a screen body 113having upper and lower screen decks 114, 115 respectively (formed of endmembers 116, cloth 117 and clamping means 118, as previously described)and provided with side plates 119,

and backing plates 121, 122 to assure that the treated material passesonly to their respective chutes 123, 124. The screen body 113 isprovided with a suitable gyrating shaft extending therethrough betweeninner bearings 131, 132 respectively carried by side plates 119, 120 andextending into suitable outer bearings 135, 136 at each end thereofwhich are carried by suitable bearing housing 137, 138 in a mannersimilar to the embodiment shown in FIG. 1.

Each bearing housing, for example housing 137, is provided withoutreaching arms 139, 140 extending oppositely from symmetrical portionsof the bearing housing and resiliently connected at their ends to thescreen body 113 with suitable shear mounts 151, 152 respectively.

Each bearing housing arm of the screen adjacent the feed end, forexample arm 139, is further provided with an upstanding plate 159 whichextends upwardly from the arm 139 to above the upper deck 114 and sideplate 119. A like plate 160 is for hearing housing extension 139a at thecomparable position on the other side of the screen body 113. Plates159, 160 are connected by a horizontal plate 161 which is suitablysecured across the, upper edges of the plates. Thus, plates 159, 161iand 161 provide a positive linkage between the outer bearing housingextensions 139, 13921. Plate 161 is further provided with a table 1 17upon which a suitable motor 146 can be mounted for a driving connectionwith a pulley 142 secured to gyrating shaft 130 through a suitablelinkage, such as V-belts 143, which extend between pulley 142 and asheave 144 secured to the motor drive shaft 145. As a variant, table 147can be omitted and motor 146 mounted directly to plate 161.

Intermediate the plates and the end of their adjacent arm, for example,between plate 159 and the end of arm 139, a suitable hanger bracket 165is provided to at-:

tach screen body 113 by a vertical hanger 166, which may be formed ofrodding, cable and the like, to suspend screen body 113 from an overheadsupporting structure 111. Interposed between the upper end of hanger 166and supporting structure 111 is supporting mount 153 which, as shown,comprises a compression spring 167 operatively interposed between a topplate 168 and a bottom plate 169 which are secured by nuts 170. A likebracket 171, hanger 172, spring 173, plates 174, and nuts 176 make up asupporting amount 154 intermediate bearing housing 137 and stabilizingmount 152. Like parts appear on the other side of the device and thosethat appear in FIGS. 5 and 6 are designated with a suffix a. Therelative lengths of hangers 166, 166a, 172 will, of course, be selectedto provide the desired inclination to body 113 While the selectivetightening of nuts 170, 176 provides an easy method for leveling out thescreen decks.

In operation, both embodiments are predicated upon essentially anidentical concept, namely, the screen body is connected directly to eachouter bearing arm by resilient stabilizing mounts while the outerbearing arms are directly connected to a stationary support structure byresilient supporting mounts. Thus, the outer hearing arms of the screenremain stationary during the normal balanced operation of the screenbecause the force of gyrations of the screen imparted to stabilizingmounts are simultaneously counteracted by an equal and opposite forceimparted by the shaft to the outer bearing arms. When, however, severeoverloading of the screen occurs, as when clumps of material strike theupper deck or material sticks thereto, an unbalance occurs because aloss of motion occurs rendering the reactive force of the bearing armsgreater than the forces of gyration in the stabilizing mounts. But thisunbalanced force must pass through the supporting mounts where they aresubstantially completely absorbed before they reach the supportingstructure. As a result, the screen is substantially completelyself-compensating and cannot be unbalanced to the state where severevibrations will be transmitted to 7 the building in which the screen ismounted. Thus, the severe wear on both supports and building normallyattendant the severe vibration of the prior screens is for all practicalpurposes substantially completely eliminated.

Thus, whereas the screens of prior art, such as the aforementioned'Parks screen, become unbalanced in operation (as when material adheresto the screen surfaces or shock loading occurs) and transmits anobjectionable amount of vibrations to the buildings, the screensembodying the present invention completely obviate this disadvantage andfulfill to a remarkably unexpected extent the objects hereinbefore setforth.

Furthermore, the Parks screen because of the continual movement of itsouter bearing during running stabilizes its body to the building so thatall shocks received therein must be transmitted through all of thescreen bearings and to the building, whereas the screen of the presentinvention obviates these disadvantages in the manner which waspreviously explained.

While only two structures embodying the present invention have beenherein described and illustrated, it is, of course, understood that suchmodifications, alterations and applications as will readily occur tothose confronted with this teaching are intended within the spirit ofthis invention, especially as it is defined by the appended claims.

Having now particularly described and ascertained the nature of my saidinvention and the manner in which it is to be performed, I declare thatwhat I claim is:

l. A screening device comprising: stationary support means; a vibratorybody having substantially parallel side Walls; a first set of bearingscarried by said side walls, one in each one of said walls and insubstantial registry with each other; a second set of bearings, onebeing adjacent each of said side Walls in spaced relationship thereto insubstantial registry with each other and out of registry with said firstset of bearings; a substantially horizontal continuous gyrating shaftengaging said first and said second set of bearings and extendingthrough said body to impart gyratory movement thereto; a bearing housingdisposed about each of said second set of bearings and having a firstand second outreaching rigid arm portion connected directly to saidhousing and extending from opposed portions of said housing; a pluralityof resilient shear mounts connected one between each of said rigid armportions adjacent the end thereof and said body to stabilize said body;and a plurality of resilent compression mounts connected one'betweeneach of said rigid arm portions and said support means intermediate saidstabilizing mount and said one of said second set of bearings and saidcompression support mount being substantially closer to said stabilizingmount than to said bearing.

2. In a screening device having a screen body in which a vibratingmechanism is mounted with projecting shaft portions journaled in outerbearing housing assemblies at opposite sides of the screen body, a pairof rigid extension arms connected directly and rigidly to each outerbearing housing to extend rigidly and oppositely from each other, aresilient stabilizing mount connecting each rigid extension arm to saidscreen body, and a resilient supporting mount connecting each rigid armto a sup port member, with the stabilizing mount and the supportingmount being separate assemblies spaced apart from each other along anaxis parallel to said arms.

3. In a screening device having a screen body in which a vibratingmechanism is mounted with projecting shaft portions journaled in outerbearing housing assemblies at opposite sides of the screen body, a pairof rigid extension arms connected directly and rigidly to each outerbearing housing to extend oppositely from each other, a resilientsupporting mount connecting each rigid extension arm to a supportmember, each rigid arm having a terminal portion projecting rigidlybeyond the supporting mount in the direction away from the outer bearinghousing, and a resilient stabilizing mount separate and spaced from eachsupporting mount along an axis parallel to said arms, the stabilizingmount connecting the terminal portion of said arm to the screen body.

References Cited in the file of this patent UNITED STATES PATENTS2,066,362 Parks Jan. 5, 1937 2,176,376 Denovan Oct. 17, 1939 2,313,765Parks Mar. 16, 1943 2,925,911 Parks Feb. 23, 1960

